Seattle Genetics, Inc. announced that Protein Design Labs, Inc. (PDL) has exercised an option for an exclusive license to an antigen target under the parties' antibody-drug conjugate (ADC) collaboration, triggering a payment to Seattle Genetics.

"The exercise of this option by PDL reflects the progress being made in our collaboration, and is recognition of the potential of ADCs as therapeutics," stated Clay Siegall, PhD, president and CEO, Seattle Genetics. "Seattle Genetics has made meaningful advances in ADC technology by improving their stability, potency and ease of manufacturing."

The ADC collaboration was originally formed in June 2001 with Eos Biotechnology, and was assumed by PDL in 2003 through its acquisition of Eos Biotechnology. Under the terms of the collaboration, PDL has a license to use Seattle Genetics' ADC technology with antibodies against targets selected by PDL. PDL pays ongoing technology access and material supply fees and has agreed to pay progress-dependent milestone payments and royalties on net sales of any resulting ADC products. PDL is responsible for research, product development, manufacturing and commercialization of any products resulting from the collaboration.

ADCs utilize the targeting ability of monoclonal antibodies to deliver potent, cell-killing payloads to specific cells. Seattle Genetics has developed improved ADC technology employing synthetic, highly potent drugs that can be attached to antibodies through proprietary linker systems. The linkers are designed to be stable in the bloodstream but to release the drug payload under specific conditions once inside target cells, thereby sparing non-target cells many of the toxic effects of traditional chemotherapy. ADCs may increase the therapeutic potential of the many antibodies with targeting ability but no inherent cell-killing activity on their own.

Seattle Genetics discovers and develops monoclonal antibody-based therapeutics to treat cancer and other human diseases. Seattle Genetics has developed leading ADC technology comprised of highly potent synthetic drugs and stable linkers for attaching the drugs to monoclonal antibodies. The company currently has license agreements for its ADC technology with Genentech, Celltech Group and Protein Design Labs.